Re: All the old UNIX source code you can eat...
I think you'll find that TFA pointed out a link to all that ... AND Unix Research Editions 8, 9, and 10. Probably the best way to access the complete archive is via ftp:
Don't blame me for the "www" in that URL ;-)
The Research UNIX archive in question is at:
For an interesting take on the un*x theme, check out Coherent:
You'll want the base & X11R5 floppy images to build a working GUI (the dos directory contains rawwrite.exe for burning floppys; you'll probably want to use dd). This thing is written in assembler, and is almost blindingly fast on a 386. It's a shame MWC went under, it had potential. Worth a look :-)
Also of interest in that archive is Xenix:
Dig through that (you'll need to use strings on the binaries) and I think you'll discover Redmond didn't write a single line of code. It's all AT&T, MS was just a re-seller of source licenses.